Telephone-exchange system.



0. w. K'ECKLER. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JULY 3. NH.

Patented Apr. 23,1918.

m yen/0r. fink/es I44 Keck/er ionirn sure arrr rron CHARLES W. KECKLER, 0F NEWARK, NEVJ JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. 1., A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Apr. as, rare.

Application filed July 3, 1917. Serial No. 178,471.

To all whom it may concern:

Be it known that 1, CHARLES W. KnoK- LER, a citizen of the United States, residing at Newark, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Telephone-EX- change Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone exchange systems and more particularly to such systems employing trunk circuits for interconnecting telephone lines terminating at different switchboards.

An object of this invention is to provide improved signaling means for such systems.

Another object of this invention is to provide a trunk circuit for such systems for cooperating with and extending calls to telephone lines of the jack cut-off type which have no sleeve circuits.

In accordance with this invention, there is provided a trunk circuit which, when the central office link circuit is connected with the outgoing end thereof a signaling device at the incoming end is operated continuously to serve as a line signal. Connection may then be completed by the incoming operator with the wanted telephone line. At the conclusion of the conversation upon the disconnection of the link circuit from the trunk circuit, apparatus associated with the trunk circuit is rendered effective for causing the signaling device to operate intermittently to furnish a disconnect signal.

For a more complete understanding of this invention, reference should be had to the following description considered in connection with the accompanying drawing containing one embodiment thereof.

In the drawing there is shown a toll switching trunk circuit A, extendingfrom a toll switchboard X to a toll switching operators position of a local switchboard Y. At the toll switchboard there is located a cord circuit B which may be connected in any desired manner with a toll telephone line C. A local telephone line D terminates at the local switchboard Y. The cord circuit B and the trunk circuit A may be employed in establishin connections between the toll telephone l1ne C and the local line D.

The toll operator, desiring to complete a connection between the toll telephone line C and the local line D, inserts plug 5 of the cord circuit B into the outgoing jack 6 of the toll switching trunk A. Relay 7 thereupon operates over a circuit from battery through the left-hand winding of relay 7, lefthand normal contact of relay 8, ring contacts of the jack 6 and plug 5, winding of supervisory relay 9, tip contacts of the plug 5 and jack 6, right-hand nor mal contact of relay 8 and the right-hand winding of relay 7 to ground. Relay 7, in operating, causes the operation of relay l0 and the lighting of lamp 11 over a circuit from battery through the winding of the relay 10 and the lamp 11 (in parallel), contact 15 of relay 16 and the alternate con tact of relay 7 to ground. Relay 10, in operating, causes the energization of relay 8 over a circuit from battery through the right-hand winding thereof and contact of relay 10 to ground. Relay 8, upon being energized, disconnects relay 7 from'the talking conductors of the trunk circuit. Relay 7 is maintained in operative condition due to a circuit from battery through the lefthand winding thereof and left-hand alternate contact of relay 8 to ground. The disconnection of relay 7 from the talking strands of the trunk circuit, prevents the operation of relay 9 in the cord circuit B, to light the lamp 22, when the toll switching operator inserts plug 5 of the toll cord circuit B into the outgoing' jack 6 of the toll switching trunk.

The toll switching operator having previously been advised over an order wire circuit (not shown) or in any other suitable manner that the incoming end of the toll switching trunk is to be connected with line D, inserts plug 17 into jack 18 thereof. The toll switching operator then momentarily actuates a key 19, which is of the non-locking type, thereby causing the operation of relay 20. Belay 20, in perating, cause the operation of relay 16 over a circuit from battery through the winding of relay 16, alternate contact of relay 20 and alternate contact of relay 7 to ground. The operation of relay 16 causes the eifacement of the lamp 11, and release of relay 2O establishes a locking circuit for relay 16 which may be traced from battery through the winding of relay 16, normal contact of relay 20, and contact 21 of relay 16 to ground. The operation of relay 16 also causes the release of relay 10, whereupon relay 8 releases, re-

connecting the relay 7 to the talking strands of the trunk circuit. The supervisory relay 9 immediately operates to cause the lighting of supervisory lamp 22, which now serves as a ringing signal to the toll operator. The toll operator may thereupon actuate ringing key 23 to connect a source of ringing current 25 to the trunk circuit. Relay 24 responds to the ringing current from source 25, causing the operation of relay 26 and relay 8 over a circuit from battery through-the left-hand winding of relay 8, Winding of relay 26 and the contact of relay 24 to ground. Relay 26, in operating, connects a source of ringing current 27 to the called line D for-causing; the actuation of the usual-call bell 28. The operation of relay 8 disconnect the relay '7 from the talking strands of the trunk circuit during the time that the ringing key 23 is actuated. The supervisory'lamp 22 is thereby eifaced while the ringing key 23 is actuated. Upon the restoration of the ringing key 23 to normal position, relays 8, 26 and 24 are released and relay 9 is actuated to cause the lighting of the supervisory lamp 22.

The subscriber D, in responding to the actuation of the call bell 28', removes the receiver from the switchhook, thereby causing the operation of supervisory relay 30. Upon the operation of supervisory relay 30, relay 8 is energized over a circuit from battery through the right-hand winding thereof, left-hand normal contact of relay 31 and contact of relay 30 to ground. The operation of relay 8 disconnects relay 7 from the talking strands of the trunk circuit, whereupon supervlsory relay 9 is released to extinguish the supervisory lamp 22, thereby serving as an indication to the toll operator that the calling subscriber has answered.

At the conclusion of the conversation, the subscribers restore the receivers to the switchhooks. The restoration of the receiver to the switchhook by subscriber D causes the deenergization of supervisory relay 30, whereupon relay 8 is deenergized to reconnect relay 7 to the talking strands of the trunk circuit. Supervisory relay 9 thereupon operates to cause the lighting of the supervisory lamp 22 to furnish a disconnect signal. The toll operator may then withdraw the plug 5 from the jack 6, thereby causing the deenergization of relay Relay 7, in releasing its armature, causes the operation of relay 31-over a circuit from battery through contact 32 of relay 16, winding of relay 31, right-hand normal contact thereof and the normal contact of relay 7 to ground. Relay 31, in operating, establishes a locking circuit for itself through its right-hand alternate contact. The release of relay 7 also completes a circuit for relay 10 and lamp 11. The lamp is thereupon lighted and relay 10 operated. Relay 10, in operating, completes an operating circuit for relay 8, which in turn causes the operation of relay 7. The actuation of relay 7 opens the circuit of relay 10 and lamp 11. Relay l0 release its armature, thereby opening the circuit of relay 8 which then, in releasing, causes the deenergization of relay 7. Relay 7 then in releasing its armature reestablishes the operating circuit through the lamp 11 and the winding of relay l0. Relays 7 and 10 are both slow to operate and slow to release so as to provide definite periods during which the lamp 11 is lighted and effaced. The lamp 11 is thus imiermittently lighted to furnish a disconnect signal to the toll switching operator, and inter1nittent lighting thereof continues until the key 19 is actuated to cause the operation of relay 20 for opening the locking circuit of relay 16. The operation of this key 19 and the withdrawal of the plug 17 from the jack 18 causes all apparatus to return to normal condition.

lVhat is claimed is:

1. In a telephone exchange system, the combination of a trunk circuit extending from' a first to a second switchboard, a naling device for the trunk circuit located at the second switchboard, a link circuit at the first switchboard, a relay in the trunk circuit responsive to the connection of the link circuit therewith for causing the operation of the signaling device, a telephone line terminating at the second switchboard and connected with the trunk circuit, means controlled by the operator at the second switch board for stopping the operation of the signaling device, and means rendered effective by the subsequent disconnection of the link circuit from the trunk circuit for causing the intermittent operation of the signaling device.

2. In a telephone exchange system, the combination. of a trunk circuit extending from a first to a second switchboard, a signaling device for the trunk circuit located at the second switchboard, a link circuit at thefirst switchboard, a relay in the trunk circuit responsive to the connection of the link circuit therewith for causing the operation of the signaling device, a telephone line terminating at the second switchboard and connected with the trunk circuit, an operator controlled key at the second switchboard, a relay energized upon the actuation of the key for stopping the operation of the signaling device, and electromagnetic means at the second switchboard responsive to the subsequent disconnection of the link circuit from the trunk circuit for causing the intermittent operation of the signaling device.

3. In a telephone exchange system, the combination of a trunk circuit extending froma first to a second switchboard, a signaling device for the trunk circuit located at the second switchboard, a link circuit at the first switchboard, a relay in the trunk circuit responsive to the connection of the link circuit therewith for causing the operation of the signaling device, a telephone line terminating at the second switchboard and connected with the trunk circuit, a switch at the second switchboard, a relay energized upon the actuation of the switch for stopping the operation or" the signaling device, a locking circuit for the relay completed upon the energization thereof, and a relay responsive to the subsequent disconnection of the link circuit from the trunk circuit while the second mentioned relay is locked up for causing the intermittent operation of the signaling device.

4-. In a telephone exchange system, the combination of a trunk circuit extending from a first to a second switchboard, a signaling device for the trunk circuit located at the second switchboard, a link circuit at the first switchboard, a relay in the trunk circuit responsive to the connection of the link circuit therewith for causing the opera tion of the signaling device, a telephone line terminating at the second switchboard and connected with the trunk circuit, a switch at the second switchboard, asecond relay energized upon the actuation of the switch for stopping the operation of the signaling device, a third relay energized upon the subsequent disconnection of the link circuit from the trunk circuit, and. a pair of relays thereupon cooperating with the first mentloned relay while the second and third relays are energized to cause the intermittent operanaling device for the trunk circuit located at the second switchboard, a link circuit at the first switchboard, a relay in the trunk circuit responsive to the connection of the link circuit therewith for causing the operation of the signaling device, a telephone line terminating at the second switchboard and con nected with the trunk circuit, a switch at the second switchboard, a second relay energized upon the actuation of the switch for stopping the operation of the signaling device, and a pair of relays rendered operative upon the subsequent disconnection of the link circuit from the trunk circuit for cooperating with the first mentioned relay while the second relay is energized to cause the intermittent operation of the signaling device.

(S. In a telephone exchange system, the combination of a trunk circuit extending from a first to a second switchboard, a signaling device for the trunk circuit located at the second switchboard, a link circuit at the first switchboard, a relay in the trunk circuit responsive to the connection of the link circuit therewith for causing the operation of the signaling device, a telephone line terminating at the second switchboard and connected with the trunk circuit, a switch at the second switchboard, a second relay energized upon the actuation of the switch for stopping the operation of the signaling device, a third relay energized upon the subsequent disconnection of the link circuit from the trunk circuit, and a pair of relays thereafter cooperating with the first mentioned relay to cause the intermittent operation of the signaling device.

In witness whereof, I hereunto subscribe my name this 30th day of June, A. D., 1917.

CHARLES W. KECKLER.

topics 011 this patent may be obtained for five cents each. by addressing the Commissioner of Patents,

Washington, D. G. 

